The Imitation Game

import java.util.Scanner;

public class Problem1 {
    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);
        String encryptedMessage = scan.nextLine();
        String instructions = scan.nextLine();

        while (!instructions.equals("Decode")) {
            String[] tokens = instructions.split("\\|");
            String command = tokens[0];

            switch (command) {
                case "Move":
                    int numberOfLetters = Integer.parseInt(tokens[1]);
                    if(numberOfLetters >= 0 && numberOfLetters <= encryptedMessage.length()){
                        String strToMove = encryptedMessage.substring(0, numberOfLetters);
                        StringBuilder mover = new StringBuilder();
                        mover.append(encryptedMessage);
                        mover.replace(0, numberOfLetters, "");
                        mover.append(strToMove);
                        encryptedMessage = mover.toString();
                    }
                    break;
                case "Insert":
                    int insertIndex = Integer.parseInt(tokens[1]);
                    if(insertIndex >= 0 && insertIndex <= encryptedMessage.length()){
                        String value = tokens[2];
                        StringBuilder stringBuilderInserter = new StringBuilder();
                        stringBuilderInserter.append(encryptedMessage);
                        stringBuilderInserter.insert(insertIndex, value);
                        encryptedMessage = stringBuilderInserter.toString();
                    }

                    break;
                case "ChangeAll":
                    String toChange = tokens[1];
                    if(encryptedMessage.contains(toChange)){
                        String replacement = tokens[2];
                        encryptedMessage = encryptedMessage.replace(toChange, replacement);
                    }
                    break;
            }
            instructions = scan.nextLine();
        }
        System.out.print(String.format("The decrypted message is: %s",encryptedMessage));
    }
}